Preparation Of Cholesterol Lowering Peanut Polypeptide And Development Of Beverage

Peanut is one of the most widely planted crops in China and even in the world. As a by-product of peanut oil, peanut meal is mainly used as feed, so most of its protein and dietary fiber have not been fully utilized. Peanut protein is a complete protein with high nutritional value. With cold pressing, the nutritional and functional properties of peanut protein meal are preserved well. In the experiment, cold pressed peanut meal was used as raw material to optimize the enzymatic hydrolysis process of peanut polypeptide. With membrane separation technology, peanut peptides were isolated and purified and its physical and chemical properties were studied. On the basis, the peanut polypeptide beverage with cholesterol lowering activity was developed. The main results are as follows:1. Optimization of the preparation process of peanut peptides with high cholesterol lowering activity. With enzymatic hydrolysis, cold pressed peanut meal was prepared into peanut polypeptide with high cholesterol lowering activity. With the ability of peanut peptides binding to bile salts in vitro as indicator, the effects of enzyme species, temperature, pH value,enzyme addition and the time of enzymatic hydrolysis on the cholesterol lowering activity of peanut polypeptide were studied. Papaya protease was identified as the optimal protease.According to L9(34) orthogonal experiment, the optimum conditions for preparing peanut polypeptide with high cholesterol lowering activity was determined, that were temperature50 °C, pH 7.0, 4000 U/g substrate, and the hydrolysis time of 4 hours. The prepared peanut polypeptides were used for simulated digestion in vitro, and cholesterol lowering activity of its digestive products was determined.2. The research about isolation, purification and physicochemical properties of peanut polypeptide with high cholesterol lowering activity. By ultrafiltration and nanofiltration technology, peanut polypeptides were separated into seven groups of different molecular weight, and their cholesterol lowering activity was determined. The peptides of500-800 Da were identified as the one with the highest cholesterol lowering activity. And the physicochemical properties of 200-1000 Da peptides, peanut polypeptide and peanut protein,including water absorption, oil absorption, foaming, emulsification and so on, were studied.3. Peanut polypeptide beverage with the cholesterol lowering activity wasdeveloped. With the sensory evaluation and cholesterol lowering activity of two indexes, the effects of the volume ratio of polypeptide and milk, inulin, peanut flavor sucralose, fructose and oligosaccharides on peanut polypeptide beverage were studyed. According to the two groups of single factor and L9(34) orthogonal experiment, optimization formula of peanut polypeptide beverage was determined for polypeptide milk volume ratio 5:5, inulin 3 %,peanut flavor 0.03 %, sucralose 0.004 %, motosada sugar 0.10 %, oligofructose addition 3 %.The storage stability of peanut polypeptide beverage was studied, also.